1. Field of the Invention
The present invention relates to a collective conductor and a method for producing the collective conductor. More specifically, the present invention relates to the structure of a collective conductor that is formed by tying a plurality of conductive wires together, and a method for producing the collective conductor.
2. Description of Related Art
A collective conductor that is formed by tying a plurality of conductive wires together has been proposed as a conductor for use in stator coils of a motor.
Japanese Patent Application Publication No. 2008-186724 (JP 2008-186724 A) discloses a collective conductor in which a plurality of conductive wires with a rectangular cross-section is collectively arranged parallel to one another. An adhesive is applied to the side faces of the conductive wires, and the conductive wires are bonded together via the adhesive. This prevents the conductive wires from separating from each other when the conductive wires are arranged collectively. In addition, an insulating film is provided as an outermost layer around the conductive wires and ties the collectively-arranged conductive wires together.
Some conventional collective conductors have a copper foil that is wound around the collectively-arranged conductive wires with a rectangular cross-section to tie the conductive wires together. When such a collective conductor is bent into the shape of a stator coil, there is a tendency toward a smaller bend radius because of the demand for smaller motor coil ends. Thus, there is a possibility that the copper foil on the inner periphery of the collective conductor may undergo buckling distortion under compressive stress. When the copper foil undergoes buckling distortion in this way, the bend section cannot be formed into an intended shape and may interfere with the adjacent coils.